Bottles and jars – Closures – Frangible member or portion
Reexamination Certificate
1998-10-29
2001-05-01
Cronin, Stephen K. (Department: 3727)
Bottles and jars
Closures
Frangible member or portion
C215S044000, C215S330000, C222S541500, C222S551000, C222S562000
Reexamination Certificate
active
06223919
ABSTRACT:
1. TECHNICAL FIELD
The present invention relates to a plastic tube, comprising a tube body and a tube cap, for flowable or free-flowing or pasty components. In particular, the plastic tube according to the invention has an indicating strip (guarantee closure) and a cap locking mechanism which latches the tube cap to the tube body when the tube cap is screwed on to the tube body.
2. PRIOR ART
Tube cap locking mechanisms were not necessary in the tubes used earlier. These already known tubes mostly comprise a tube body, produced from aluminium, and a tube cap, produced from plastic, which were provided in each case with an industrial screw thread of complementary construction. An industrial thread is understood below as a thread for a plastic tube cap which was not positively disengaged, as is customary in the case of tube caps (by contrast with, for example, bottle caps).
An adequately reliable fastening of the tube cap on the tube body was achieved by virtue of the fact that the cooperating screw threads were constructed with as fine a pitch as possible, so that owing to the correspondingly small thread pitch and to the aluminium/plastic material combination, the cap held on the tube body sufficiently firmly when it was screwed on with adequate tightness. This prevented inadvertent detachment or else only loosening of the tube cap from the tube body.
However, tubes consisting of aluminium (or another metal) have recently been increasingly fading into the background; they are more and more being replaced by tubes consisting entirely of plastic. Furthermore, requirements placed on tubes with regard to the screw thread have recently been changed: repeated rotation of the tube cap which is required to achieve the sealing effect, in both meanings, of the tube closure in the case of fine threads is nowadays felt to be an imposition. Moreover, in the case of a fine thread the screw thread of the tube cap must be brought very exactly into position with regard to the screw thread of the tube, in order to permit the tube cap to be screwed on without tilting.
For these reasons, increased use is currently being made of coarse threads with a high thread pitch which, on the one hand, permits the tube cap to be screwed on with a few turns and, on the other hand, render it unnecessary to position the screw thread of the tube cap and of the tube body accurately with respect to one another. These recent tube caps have the disadvantage, however, that the tube cap easily becomes detached or else can merely become loosened, as a result of which the tube components can escape from the tube and/or an adequate seal is no longer achieved.
A further problem of previously known tubes occurs in connection with the current environmental requirements. Whereas previously each individual tube was also provided with an enveloping package in the form of a small cardboard box, this additional package is dispensed with nowadays in order to avoid refuse. The enveloping packages used previously had the advantage that it was easy to seal the package in a simple way using a sticker which was destroyed when the package was opened for the first time. It was possible in this way for the customer to establish without difficulty that he was acquiring a tube which was acceptable because it was unopened. This simple measure of ensuring quality is no longer possible with the elimination of the enveloping packages.
As an alternative, a type of adhesive seal which was stuck over the joint between the tube cap and tube body was therefore taken into consideration for tubes offered without enveloping packaging. When the tube cap was turned for the first time, the adhesive seal was broken, and so the customer could see whether the tube had already been opened or not.
A disadvantage of this sealing technique resides in the possibility that after the tube has been opened for the first time a new seal is stuck on to the joint, thus giving the impression of an intact tube. A further disadvantage resides in the fact that when checking the integrity of the seal it is necessary to keep turning the tube until the seal can be seen—an activity which can be very time consuming and laborious.
Also known are other sealing techniques, which have a pin which is arranged on the cap shoulder and is connected to the cap. Upon first-time opening by raising the cap, this pin breaks and therefore indicates that the tube is not intact. Also known are seals which have a transverse tab which must be torn off before opening the tube.
These seals likewise have the disadvantage that they can be seen only from one side of the tube, with the result that the tube must firstly be turned, as in the case of the seal previously described. Furthermore, tearing off the transverse tab produces refuse which must additionally be disposed of, and both the pin and the transverse tab can be produced only expensively in term of production engineering.
The printed publication DE 83 01 345 U1 describes a tube for sensitive filled products, which comprises a tube body provided with a screw thread, and tube cap provided with a complementary screw thread. Until first use is made, the previously known tube also has an additional sealing closure which is arranged in the interior of the cap lid in such a way that it seals the outlet end of the tube body
GB 1 269 723 has disclosed a tube with a plastic cap and a metal body. The cap from this printed publication is provided with an additional collar part which is connected to the tube cap by means of connecting labels.
With regard to the above prior art, the present invention is therefore based on the technical problem of creating a plastic tube which comprises a tube cap and tube body and, on the one hand, permits the tube cap to be fastened on the tube body in a way which ensures sealing and holds even in the case of screw threads with a large thread pitch and which, on the other hand, has a seal which is easy to see and operates reliably even with small plastic tubes.
3. SUMMARY OF THE INVENTION
The present invention solves the above problem by means of a plastic tube which, in accordance with patent claim
1
, has a locking mechanism comprising a locking cam and a latching cutout.
Furthermore, the present invention solves the above problem by means of a plastic tube which, in accordance with patent claim
17
, has a sealing strip constructed on the tube cap.
The present invention comprises elements which are complementary both with regard to the sealing strip and with regard to the locking mechanism, and which are arranged in each case on the tube body and the tube cap. Consequently, the aim of the invention is not only to protect the respective combination of tube cap and tube body, but also to protect the respective tube cap and tube body in themselves.
In accordance with the present invention, in addition to the conventional screw thread the plastic tube according to the invention is provided with a tube locking mechanism which comprises at least one locking cam and a cutout of complementary construction which receives the locking cam. The locking of the tube is achieved with the aid of the locking mechanism according to the invention by virtue of the fact that the tube cap is mounted on the tube body and then screwed on as far as an end position in which the locking cam jumps elastically into the cutout and latches therein.
In addition to the locking cam, the tube cap advantageously also has a positive disengaging step. This is advantageously arranged close against the locking cams in a fashion displaced towards the top side of the tube cap, and has the effect that when being positively disengaged the locking cams are scarcely damaged. Specifically, when being positively disengaged the positive disengaging step causes preliminary straining of the tube cap, which largely prevents the deformation of the locking cams. The inventor of the present invention has carried out tests and found in the process that, given a tube cap which is identical per se, the positive disengaging step permits substantially improved latching of the
Cronin Stephen K.
Renner , Otto, Boisselle & Sklar, LLP
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